ANAHEIM, Calif. — What does it look like when baseball’s most curveball-reliant starter loses the feel for his trademark pitch?

We’re finding out now.

Lance McCullers Jr. has for much of this season lacked the same sharp, late bite on the power curveball that has baffled major league hitters since May 2015. The pitch’s average velocity has been up, its spin rate down and its shape more lateral than usual, more like a slider.

So in the Astros’ 2-1 loss Monday night at Angel Stadium, McCullers made his famous pitch his third pitch. For the first time in his career, he threw more changeups (27) than curveballs (21). With his two-seam fastball and changeup combo working as well as ever, he managed to hold a dangerous Angels lineup to only two runs in six innings.

“It’s just how it’s been so far this year,” McCullers said. “I just haven’t hit my stride. I’ve been kind of grinding...